Gut and respiratory tract microbiota in children younger than 12 months hospitalized for bronchiolitis compared with healthy children: can we predict the severity and medium-term respiratory outcome?

Growing evidence indicates that gut and respiratory microbiota have a potential key effect on bronchiolitis, mainly caused by respiratory syncytial virus (RSV). This was a prospective study of 96 infants comparing infants with bronchiolitis (n = 57, both RSV and non-RSV associated) to a control group (n = 39). Gut (feces) and respiratory [nasopharyngeal aspirate (NPA)] microbial profiles were analyzed by 16S rRNA amplicon sequencing, and respiratory viruses were identified by PCR. Clinical data of the acute episode and follow-up during the first year after infection were recorded. Pairwise comparisons showed significant differences in the gut (R2 = 0.0639, P = 0.006) and NPA (R2 = 0.0803, P = 0.006) microbiota between cases and controls. A significantly lower gut microbial richness and an increase in the NPA microbial diversity (mainly due to an increase in Haemophilus, Streptococcus, and Neisseria) were observed in the infants with bronchiolitis, in those with the most severe symptoms, and in those who subsequently developed recurrent wheezing episodes after discharge. In NPA, the higher microbial richness differed significantly between the control group and the non-RSV bronchiolitis group (P = 0.01) and between the control group and the RSV bronchiolitis group (P = 0.001). In the gut, the richness differed significantly between the control group and the non-RSV group (P = 0.01) and between the control group and the RSV bronchiolitis group (P = 0.001), with higher diversity in the RSV group. A distinct respiratory and intestinal microbial pattern was observed in infants with bronchiolitis compared with controls. The presence of RSV was a main factor for dysbiosis. Lower gut microbial richness and increased respiratory microbial diversity were associated with respiratory morbidity during follow-up. IMPORTANCE: Both the intestinal and respiratory microbiota of children with bronchiolitis, especially those with respiratory syncytial virus infection, are altered and differ from that of healthy children. The microbiota pattern in the acute episode could identify those children who will later have other respiratory episodes in the first year of life. Preventive measures could be adopted for this group of infants.

The role of veterinarians in zoonosis prevention: Advising families of immunocompromised children with pets.

Background: Pet ownership is widespread, offering numerous benefits to individuals and families. However, the risk of zoonotic diseases must be carefully considered, especially for immunosuppressed patients. Knowledge gaps in preventive measures for zoonoses have been identified, underscoring the vital role of veterinarians in addressing this issue. Objectives: This study aimed to assess the knowledge and recommendations of veterinarians regarding pet ownership by immunocompromised individuals. Additionally, we compared these insights with responses from European healthcare professionals specializing in pediatric transplant recipients. Methods: We conducted an observational, cross-sectional study involving small animal veterinarians in Spain. An online survey was administered to gather information on veterinarians' knowledge of zoonoses and their recommendations for immunocompromised pet owners. Results: A survey of 514 individuals was collected from experienced veterinarians mainly working in primary care clinics. Surprisingly, 63% of respondents did not routinely inquire about the presence of immunocompromised individuals among pet owners, although 54% offered specific recommendations for this group. Most respondents adhered to deworming guidelines for pets owned by immunocompromised individuals and demonstrated sound practices in Leishmania and Leptospira prevention, as well as the avoidance of raw food. However, gaps were noted concerning Bordetella bronchiseptica vaccination. Notably, veterinarians outperformed medical professionals in their knowledge of zoonotic cases and identification of zoonotic microorganisms. The presence of specific recommendations in veterinary clinics was viewed positively by nearly all respondents. Conclusions: Our findings indicate that veterinarians possess a superior understanding of zoonotic pathogens and exhibit greater proficiency in diagnosing zoonoses compared with physicians. They stay well-informed about recommendations outlined in established guidelines and are more likely to provide written recommendations in their clinics than physicians. Nevertheless, knowledge gaps among veterinarians emphasize the need for enhanced communication between medical and veterinary professionals. Reinforcing the "One Health" concept is imperative, with veterinarians playing a pivotal role in this collaborative effort.

Antibiotic Utilization in Hospitalized Children with Bronchiolitis: A Prospective Study Investigating Clinical and Epidemiological Characteristics at a Secondary Hospital in Madrid (2004-2022).

Bronchiolitis is a viral respiratory infection, with respiratory syncytial virus (RSV) being the most frequent agent, requiring hospitalization in 1% of affected children. However, there continues to be a noteworthy incidence of antibiotic prescription in this setting, further exacerbating the global issue of antibiotic resistance. This study, conducted at Severo Ochoa Hospital in Madrid, Spain, focused on antibiotic usage in children under 2 years of age who were hospitalized for bronchiolitis between 2004 and 2022. In that time, 5438 children were admitted with acute respiratory infection, and 1715 infants (31.5%) with acute bronchiolitis were included. In total, 1470 (87%) had a positive viral identification (66% RSV, 32% HRV). Initially, antibiotics were prescribed to 13.4% of infants, but this percentage decreased to 7% during the COVID-19 pandemic thanks to adherence to guidelines and the implementation of rapid and precise viral diagnostic methods in the hospital. HBoV- and HAdV-infected children and those with viral coinfections were more likely to receive antibiotics in the univariate analysis. A multivariate logistic regression analysis revealed a statistically independent association between antibiotic prescription and fever > 38 °C (p < 0.001), abnormal chest-X ray (p < 0.001), ICU admission (p = 0.015), and serum CRP (p < 0.001). In conclusion, following guidelines and the availability of rapid and reliable viral diagnostic methods dramatically reduces the unnecessary use of antibiotics in infants with severe bronchiolitis.

Surveillance of Viral Respiratory Infections in the Neonatal Intensive Care Unit-Evolution in the Last 5 Years.

Viral respiratory infections (VRIs) in very low birthweight infants can be associated with high rates of morbidity. The COVID-19 pandemic has exerted a strong impact on viral circulation. The purpose of this study is to report on VRIs during NICU admission in infants below 32 weeks' gestation and compare data collected between the pre-and post-COVID-19 pandemic periods. A prospective surveillance study was conducted at a tertiary NICU between April 2016 and June 2022. The COVID-19 post-pandemic period was established as being from March 2020 onwards. Respiratory virus detection was performed by real-time multiplex PCR assays in nasopharyngeal aspirates (NPAs). A total of 366 infants were enrolled. There were no statistical differences between periods regarding infants' birth weight, gestational age, gender distribution, or rates of bronchopulmonary dysplasia. Among the 1589 NPA collected during the pre-COVID-19 period, 8.9% were positive, and among the 1147 NPA collected during the post-pandemic period, only 3% were positive (p < 0.005). The type of viruses detected did not differ according to the study period (pre-COVID19 vs. post-COVID-19): rhinovirus (49.5% vs. 37.5%), adenovirus (22.6% vs. 25%), and human coronavirus (12.9% vs. 16.7%). SARS-CoV-2 was only detected in one patient. In conclusion, the viral profile causing VRI during the pre-COVID-19 and post-COVID-19 era was similar. However, the total number of VRI dropped significantly, most probably due to the global increase in infection prevention measures.

Torque Teno Virus in Nasopharyngeal Aspirate of Children With Viral Respiratory Infections.

BACKGROUND: Torque teno virus (TTV) is a ubiquitous anellovirus responsible for persistent infections and is considered a marker of immune function. The role of TTV as a facilitator of respiratory infections (RIs) is unknown. OBJECTIVES: Our aim was to estimate, in a prospective study, the prevalence of TTV in the nasopharyngeal aspirate (NPA) of hospitalized children <5 years old, with RIs and correlate them with outcomes and immune response. PATIENTS AND METHODS: NPA was taken for testing of 16 respiratory viruses by reverse transcription-polymerase chain reaction (PCR), TTV PCR, and immunologic study. RESULTS: Sixty hospitalized children with an RI were included. A total of 51/60 patients had positive common respiratory viral (CRV) identification. A total of 23/60 (38.3%) children were TTV+ in NPA. TTV+ patients had other CRVs in 100% of cases versus 78.3% in TTV- ( P = 0.029). The TTV+ patients tended to be older, have fever, and to need pediatric intensive care unit admission more often than TTV- patients. Abnormal chest radiograph was more frequent in the TTV+ patients, odds ratios 2.6 (95% CI: 1.3-5.2). The genetic expression of filaggrin (involved in epithelial barrier integrity) was lower in TTV+ patients; however, the levels of filaggrin in the NPA were increased. CONCLUSIONS: TTV infection is common in children with RI and could be associated with abnormal imaging in radiograph, greater severity and an alteration in filaggrin gene expression and protein release.

Balancing the Risks and Benefits of Pet Ownership in Pediatric Transplant Recipients.

In recent decades, the number of pediatric transplantations and their survival rates have increased. Psychological problems and poorer quality of life are notable among children undergoing transplantation and can have long-lasting consequences and affect immunosuppressive therapy adherence. Pet ownership and animal contact have been associated with physical, mental, and social health benefits. Despite these potential benefits, however, companion animals are known to be a source of infection, which is one of the main concerns for clinicians. Because of immunosuppression, these children are particularly vulnerable to infections. Zoonoses comprise a long list of infectious diseases and represent a major public health problem. Nevertheless, many families and most healthcare providers are unaware of these potential risks, and there is a worrisome lack of recommendations to manage the risk-benefit balance, which could pose a risk for acquiring a zoonosis. Furthermore, no data are available on the number of transplanted patients with pets, and this risk-benefit balance is difficult to adequately evaluate. In this document, we review the currently available evidence regarding the epidemiology of zoonotic infections in patients undergoing transplantation, focusing on pediatric patients from a risk-benefit perspective, to help inform decision-making for clinicians. Families and healthcare professionals should be aware of the risks, and clinicians should actively screen for pets and offer comprehensive information as part of routine clinical practice. A multidisciplinary approach will ensure proper care of patients and pets and will establish preventive measures to ensure patients are safe living with their pets.

Filaggrin and cytokines in respiratory samples of preterm infants at risk for respiratory viral infection.

Respiratory viral infections (RVIs) are frequent in preterm infants possibly inducing long-term impact on respiratory morbidity. Immune response and respiratory barriers are key defense elements against viral insults in premature infants admitted to Neonatal Intensive Care Units (NICUs). Our main goals were to describe the local immune response in respiratory secretions of preterm infants with RVIs during NICU admission and to evaluate the expression and synthesis of lung barrier regulators, both in respiratory samples and in vitro models. Samples from preterm infants that went on to develop RVIs had lower filaggrin gene and protein levels at a cellular level were compared to never-infected neonates (controls). Filaggrin, MIP-1α/CCL3 and MCP-1 levels were higher in pre-infection supernatants compared to controls. Filaggrin, HIF-1α, VEGF, RANTES/CCL5, IL-17A, IL-1ß, MIP-1α and MIP-1ß/CCL5 levels were higher during and after infection. ROC curve and logistic regression analysis shows that these molecules could be used as infection risk biomarkers. Small airway epithelial cells stimulated by poly:IC presented reduced filaggrin gene expression and increased levels in supernatant. We conclude that filaggrin gene and protein dysregulation is a risk factor of RVI in newborns admitted at the NICU.

SARS-CoV-2 Infection in Children and Adolescents Living With HIV in Madrid.

Multicenter study designed to describe epidemiologic and clinical characteristics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive cases registered among children and adolescents living with HIV (CALWH). SARS-CoV-2 infection was confirmed in 13.3% of CALWH, with all patients presenting mild symptoms, and the outcome was good in all patients. None of the HIV- and antiretroviral treatment-related variables studied were associated with greater infection risk or could be considered protective.

Long-Term Persistence of Anti-SARS-CoV-2 Antibodies in a Pediatric Population.

BACKGROUND: Antibody dynamics over time after SARS-CoV-2 infection are still unclear, and data regarding children are scarce. METHODS: A prospective cohort study was performed including children infected by SARS-CoV-2 between March and May 2020. Patients were categorized into 3 groups: children admitted with COVID-19; outpatient children with mild COVID-19; and seropositive children participating in a seroprevalence study among cohabitants of infected healthcare workers (HCWs). Six months after the infection, a new serological control was performed. RESULTS: A total of 58 children were included, 50% male (median age 8.3 [IQR 2.8-13.5] years). The median time between the two serological studies was 186 (IQR 176-192) days, and 86% (48/56) of the children maintained positive IgG six months after the infection. This percentage was 100% in admitted patients and 78% among the rest of the included children (p = 0.022). The diagnoses of lower respiratory tract infection and multisystemic inflammatory syndrome were associated with persistence of IgG (p = 0.035). The children of HCWs in the seroprevalence study lost antibodies more often (p = 0.017). Initial IgG titers of the children who remained positive six months after the infection were significantly higher (p = 0.008). CONCLUSIONS: Most children infected by SARS-CoV-2 maintain a positive serological response six months after the infection. Those children who lost their IgG titer were more frequently asymptomatic or mildly symptomatic, presenting with low antibody titers after the infection.

High Rates of SARS-CoV-2 Family Transmission in Children of Healthcare Workers During the First Pandemic Wave in Madrid, Spain: Serologic Study.

BACKGROUND: Data on SARS-CoV-2 transmission among children living with healthcare workers (HCWs) are scarce. METHODS: A cross-sectional study was performed at a tertiary Hospital in Madrid, including children of HCW who suffered from SARS-CoV-2 infection between March and May 2020. Children underwent enzyme-linked immunosorbent serological study for detecting SARS-CoV-2 antibodies: VIRCELL IgG assay. RESULTS: One hundred thirteen children from 69 HCWs with confirmed SARS-CoV-2 infection were recruited: 47 children had positive IgG (41.6%). Children secondary attack rate was 43.7% (25% if both parents have had asymptomatic infection; 39.5% if one parent was symptomatic; and 47% when both parents had symptoms). Having a positive sibling was associated with a positive IgG result (odds ratio = 12.2; 95% confidence interval: 4.4-33.7, P < 0.001). Median age was higher in IgG positive children (P = 0.022). Children who referred anosmia presented higher IgG titles (P < 0.04). CONCLUSIONS: We observed a very high SARS-CoV-2 transmission in children of HCW during the first pandemic wave, especially when both parents were symptomatic. Having a positive sibling was associated with seroconversion, supporting the important role of family clusters in the transmission of SARS-CoV-2.

A 14-year Prospective Study of Human Coronavirus Infections in Hospitalized Children: Comparison With Other Respiratory Viruses.

BACKGROUND: Human coronaviruses (HCoVs) have been recognized as causative agents of respiratory tract infections.Our aim was to describe HCoV infections in hospitalized children in a prospective surveillance study for 14 years and compare them with other respiratory viruses. METHODS: As a part of an ongoing prospective study to identify the etiology of viral respiratory infections in Spain, we performed the analysis of HCoV infections in children hospitalized in a secondary hospital in Madrid, between October 2005 and June 2018. Clinical data of HCoV patients were compared with those infected by rhinovirus, respiratory syncytial virus and influenza. RESULTS: The study population consisted of 5131 hospitalizations for respiratory causes in children. A total of 3901 cases (75.9%) had a positive viral identification and 205 cases (4.1%) were positive for HCoV. Only 41 cases (20%) of HCoV infection were detected as single infections. Episodes of recurrent wheezing were the most common diagnosis, and 112 children (54%) had hypoxia. Clinical data in HCoV cases were similar to those associated with rhinovirus; however, patients with HCoV were younger. Other viruses were associated with hypoxia more frequently than cases with HCoV; high fever was more common in influenza infections and bronchiolitis in respiratory syncytial virus group. Although a slight peak of circulation appears mostly in winter, HCoV has been detected throughout the year as well. CONCLUSIONS: HCoV infections represent a small fraction of respiratory infections that require hospitalization in children and their characteristics do not differ greatly from other respiratory viral infections.

Expression of IL-1α correlates with distant metastasis in patients with head and neck squamous cell carcinoma.

The presence of IL-1 in human cancers is associated with aggressive tumor biology but its prognostic value is unknown. We studied whether IL-1α expression is a prognostic marker of distant metastasis in patients with head and neck squamous cell carcinoma (HNSCC). IL-1α mRNA and protein levels were determined in tumor samples and cancer cell lines using RT-PCR and ELISA. The effects of constitutive IL-1α expression by tumor lines were characterized. IL-1α mRNA and protein secretion were higher in tumor samples from patients who later developed distant metastasis than in patients who did not. By using distant metastasis as a dependent variable, patients were classified into two categories of IL-1α transcript-levels. The high-IL-1α group had a significantly lower five-year distant metastasis-free survival than the low-IL-1α group [70.0% (CI 95%: 55.9-84.1%) vs 94.7% (CI 95%:90.2-99.2%)]. When IL-1α transcript-levels were combined with clinical factors related to tumor metastasis, the predictive power of the model increased significantly. Additionally, transcript levels of IL-1α correlated significantly with those of the IL-1 family genes and genes related to the metastatic process. IL-1 treatment of microvascular endothelial cells increased adhesion of HNSCC cells but no differences were found based on constitutive IL-1α expression by tumor cells. Nevertheless, IL-1α produced by tumor cells effectively increased their transmigration across the endothelium. We found a significant relationship between IL-1α expression and development of distant metastasis in HNSCC patients. IL-1α expression could help to define a subset of patients at high risk of distant metastasis who could benefit from adjuvant treatment.

Prostacyclin-synthase expression in head and neck carcinoma patients and its prognostic value in the response to radiotherapy.

Prostacyclin (PGI2 ) plays a role in cancer progression but the mechanism is currently poorly understood. Additionally, no data are available about the prognostic value of the PGI2 pathway in head and neck squamous cell carcinoma (HNSCC) therapy. We evaluated the expression of the PGI2 pathway in HNSCC patients. PGI2 production and PGI synthase (PGIS) expression, in terms of mRNA (RT-PCR) and protein (immunoblotting), were lower in tumour samples than in non-tumoural mucosa, whereas, as expected, COX-2 expression was increased in HNSCC tumour samples. Using local control of the tumour after radiotherapy or chemoradiotherapy as a dependent variable, patients were classified into two categories of PGIS transcript levels. The high-PGIS group had a significantly lower frequency of local and distant failure than the low-PGIS group, and the 5-year cancer-specific survival was higher [90.2% (95% CI 81.0-99.4%) versus 60.5% (95% CI 44.4-76.6%)]. None of the four HNSCC cell lines analysed expressed PGIS and therefore they did not produce PGI2 . However, HNSCC-conditioned media enhanced PGI2 production in endothelial cells (ECs). The stable analogue of PGI2 , carbaprostacyclin (cPGI2 ), exerted little effect on HNSCC cell line migration, and no effect on cell cycle distribution or proliferation rate after radiation injury was observed. Nevertheless, cPGI2 promoted EP-4-dependent in vitro angiogenesis. Von Willebrand factor expression (EC marker) and capillary density were significantly higher in the group of patients with high expression of PGIS. Our results indicate that PGIS expression was associated with radiotherapy efficiency. Although we do not provide direct evidence of a relationship between tumour vascularization and radiotherapy efficiency, our results suggest that the effect of PGI2 is related to its ability to promote vascularization. These results also support the concept that co-adjuvant therapy with PGIS enhancers, such as retinoids, could have therapeutic value for HNSCC treatment.

Microvascular COX-2/mPGES-1/EP-4 axis in human abdominal aortic aneurysm.

We investigated the prostaglandin (PG)E2 pathway in human abdominal aortic aneurysm (AAA) and its relationship with hypervascularization. We analyzed samples from patients undergoing AAA repair in comparison with those from healthy multiorgan donors. Patients were stratified according to maximum aortic diameter: low diameter (LD) (<55 mm), moderate diameter (MD) (55-69.9 mm), and high diameter (HD) (≥70 mm). AAA was characterized by abundant microvessels in the media and adventitia with perivascular infiltration of CD45-positive cells. Like endothelial cell markers, cyclooxygenase (COX)-2 and the microsomal isoform of prostaglandin E synthase (mPGES-1) transcripts were increased in AAA (4.4- and 1.4-fold, respectively). Both enzymes were localized in vascular cells and leukocytes, with maximal expression in the LD group, whereas leukocyte markers display a maximum in the MD group, suggesting that the upregulation of COX-2/mPGES-1 precedes maximal leukocyte infiltration. Plasma and in vitro tissue secreted levels of PGE2 metabolites were higher in AAA than in controls (plasma-controls, 19.9 ± 2.2; plasma-AAA, 38.8 ± 5.5 pg/ml; secretion-normal aorta, 16.5 ± 6.4; secretion-AAA, 72.9 ± 6.4 pg/mg; mean ± SEM). E-prostanoid receptor (EP)-2 and EP-4 were overexpressed in AAA, EP-4 being the only EP substantially expressed and colocalized with mPGES-1 in the microvasculature. Additionally, EP-4 mediated PGE2-induced angiogenesis in vitro. We provide new data concerning mPGES-1 expression in human AAA. Our findings suggest the potential relevance of the COX-2/mPGES-1/EP-4 axis in the AAA-associated hypervascularization.

Overexpression of the nuclear factor-kappa B (p65) in association with local failure in patients with head and neck carcinoma undergong radiotherapy or chemoradiotherapy.

BACKGROUND: The aim of this study was to evaluate nuclear factor-kappa B (NF-κB) expression as a biologic marker to predict local control in patients with head and neck squamous cell carcinoma (HNSCC) treated with radiotherapy or chemoradiotherapy. METHODS: The mRNA expression levels of the NF-κB family genes were determined with real-time-polymerase chain reaction in 77 patients with HNSCC treated with radiotherapy or chemoradiotherapy. RESULTS: The mRNA NF-κB (p65) expression in pretreatment tumors was significantly related to local control (p = .03). The 5-year local recurrence-free survival rate in patients with low-level NF-κB (p65) expression (n = 42) was 79.9%, and in patients with a high level of expression it was 42.1% (p = .001). In a multivariate analysis, the mRNA NF-κB (p65) expression level was the only variable related to local control of the tumor. CONCLUSION: Expression of the NF-κB (p65) gene may be a radiosensitivity marker for patients with a HNSCC.

Genetic determinants of 5-lipoxygenase pathway in a Spanish population and their relationship with cardiovascular risk.

OBJECTIVE: Leukotrienes (LT) play a role in inflammation, cardiovascular diseases, and cancer. Although some studies suggest that there are genes that determine variability of some LT-related phenotypes, the genetic influence on these phenotypes has not been evaluated. METHODS: The relative contributions of genetic and environmental influences to the 5-lipoxygenase pathway-related phenotypes (5-Lipoxygenase, five lipoxygenase activating protein (FLAP), LTA(4)-hydrolase and LTC(4)-synthase expression, and LTB(4)-plasma concentration and LTB(4) production by stimulated whole blood) were assessed in a sample of 934 individuals in 35 extended families. Our design is based on extended families recruited through a probands with idiopathic thrombophilia. This strategy allows us the analysis of the effects of measured covariates (such as sex, age and smoking), genes, and environmental variables shared by members of a household. RESULTS: All of these phenotypes showed significant genetic contributions, with heritabilities ranging from 0.33 to 0.51 for enzyme expression and from 0.25 to 0.50 for LTB(4) production of the residual phenotypic variance. Significant phenotypic and genetic correlation among the LT-related traits was found. More importantly, FLAP and LTA(4)-hydrolase expression exhibit significant genetic correlations with arterial thrombosis, indicating that some of the genes that influence quantitative variation in these phenotypes also influence the risk of thrombosis. CONCLUSION: This is the first study that quantifies the genetic component of 5-Lipoxygenase pathway phenotypes. The high heritability of these traits and the significant genetic correlations between arterial thrombosis and some of these phenotypes suggest that the exploitation of correlated quantitative phenotypes will aid the search for susceptibility genes.

Interaction between head and neck squamous cell carcinoma cells and fibroblasts in the biosynthesis of PGE2.

Prostaglandin (PG)E(2) is relevant in tumor biology, and interactions between tumor and stroma cells dramatically influence tumor progression. We tested the hypothesis that cross-talk between head and neck squamous cell carcinoma (HNSCC) cells and fibroblasts could substantially enhance PGE(2) biosynthesis. We observed an enhanced production of PGE(2) in cocultures of HNSCC cell lines and fibroblasts, which was consistent with an upregulation of COX-2 and microsomal PGE-synthase-1 (mPGES-1) in fibroblasts. In cultured endothelial cells, medium from fibroblasts treated with tumor cell-conditioned medium induced in vitro angiogenesis, and in tumor cell induced migration and proliferation, these effects were sensitive to PGs inhibition. Proteomic analysis shows that tumor cells released IL-1, and tumor cell-induced COX-2 and mPGES-1 were suppressed by the IL-1-receptor antagonist. IL-1α levels were higher than those of IL-1ß in the tumor cell-conditioning medium and in the secretion from samples obtained from 20 patients with HNSCC. Fractionation of tumor cell-conditioning media indicated that tumor cells secreted mature and unprocessed forms of IL-1. Our results support the concept that tumor-associated fibroblasts are a relevant source of PGE(2) in the tumor mass. Because mPGES-1 seems to be essential for a substantial biosynthesis of PGE(2), these findings also strengthen the concept that mPGES-1 may be \a target for therapeutic intervention in patients with HNSCC.

Hypoxia upregulates PGI-synthase and increases PGI2 release in human vascular cells exposed to inflammatory stimuli.

Hypoxia affects vascular function and cell metabolism, survival, growth, and motility; these processes are partially regulated by prostanoids. We analyzed the effect of hypoxia and inflammation on key enzymes involved in prostanoid biosynthesis in human vascular cells. In human vascular smooth muscle cells (VSMC), hypoxia and interleukin (IL)-1ß synergistically increased prostaglandin (PG)I2 but not PGE2 release, thereby increasing the PGI2/PGE2 ratio. Concomitantly, these stimuli upregulated cyclooxygenase-2 (COX-2) expression (mRNA and protein) and COX activity. Interestingly, hypoxia enhanced PGI-synthase (PGIS) expression and activity in VSMC and human endothelial cells. Hypoxia did not significantly modify the inducible microsomal-PGE-synthase (mPGES)-1. Hypoxia-inducible factor (HIF)-1α-silencing abrogated hypoxia-induced PGIS upregulation. PGIS transcriptional activity was enhanced by hypoxia; however, the minimal PGIS promoter responsive to hypoxia (-131 bp) did not contain any putative hypoxia response element (HRE), suggesting that HIF-1 does not directly drive PGIS transcription. Serial deletion and site-directed mutagenesis studies suggested several transcription factors participate cooperatively. Plasma levels of the stable metabolite of PGI2 and PGIS expression in several tissues were also upregulated in mice exposed to hypoxia. These data suggest that PGIS upregulation is part of the adaptive response of vascular cells to hypoxic stress and could play a role in counteracting the deleterious effect of inflammatory stimuli.

Heritability of thromboxane A2 and prostaglandin E2 biosynthetic machinery in a Spanish population.

OBJECTIVE: Prostanoids play a critical role in clinical areas such as inflammation, thrombosis, immune response, and cancer. Although some studies suggest that there are genes that determine variability of some prostanoid-related phenotypes, the genetic influence on these traits has not been evaluated. METHODS AND RESULTS: The relative contributions of genetic and environmental influences to the prostanoid biosynthetic pathway-related phenotypes, cyclooxygenase isoenzymes, microsomal-PGE-synthase-1 and TxA-synthase expression, and thromboxane-A(2) and prostaglandin-E(2) production by stimulated whole blood, were assessed in a sample of 308 individuals in 15 extended families. The effects of measured covariates (such as sex, age, and smoking), genes, and environmental variables shared by members of a household were quantified. Heritabilities ranging from 0.406 to 0.634 for enzyme expression and from 0.283 to 0. 751 for prostanoid production were found. CONCLUSIONS: These results demonstrate clearly the importance of genetic factors in determining variation in phenotypes that are components of the prostanoid biosynthetic pathways. The presence of such strong genetic effects suggest that it will be possible to localize previously unknown genes that influence quantitative variation in these phenotypes, some of which affect multiple aspects of cell biology, with important clinical implications.

Tumour cell lines HT-29 and FaDu produce proinflammatory cytokines and activate neutrophils in vitro: possible applications for neutrophil-based antitumour treatment.

There is evidence that polymorphonuclear neutrophils (PMNs) can exert severe antineoplastic effects. Cross-talk between tumour cells and endothelial cells (ECs) is necessary for the accumulation of PMN around a tumour. This work reports the ability of two PMN-sensitive, human, permanent cell lines-colorectal adenocarcinoma (HT-29) and pharyngeal squamous-cell carcinoma (FaDu) cells-to act as inflammatory foci. PMNs were cytotoxic to both lines, the adhesion of the PMNs to the tumour cells being important in this effect. The tumour cells released appreciable amounts of IL-8 and GROalpha, and induced the transmigration of PMN through human microvascular-EC monolayers. Conditioning media associated with both lines induced the adhesion of PMN and the surface expression of ICAM-1 in microvascular-EC. In addition, FaDu-conditioning-medium strongly induced the production of proinflammatory cytokines by microvascular-EC. These results support the idea that tumour cells might normally induce a potent acute inflammatory response, leading to their own destruction.